Q.1 (ix) A bar magnet of magnetic moment 10 A m ² has a cross-sectional area of 2.5 × 10⁻⁴ m ² . If the intensity of magnetisation of magnet is 10⁶ A/m, the length of the bar magnet is _____. A. 2 cm B. 4 cm C. 6 cm D. 8 cm

Answer: B. 4 cm Answer: (b) 4 cm Intensity of magnetisation M_z = m/V = m/A l , so l = m/M_z A = frac1010⁶ × 2.5×10⁻⁴ = 10/250 = 0.04\ m = 4\ cm

A bar magnet of magnetic moment 10 A m\(^2\) has a cross-sectional area of \(2.5 \times 10^{-4}\) m\(^2\). If the intensity of magnetisation of magnet is \(10^6\) A/m, the length of the bar magnet is _____.

Q.1 (ix) A bar magnet of magnetic moment 10 A m\(^2\) has a cross-sectional area of \(2.5 \times 10^{-4}\) m\(^2\). If the intensity of magnetisation of magnet is \(10^6\) A/m, the length of the bar magnet is _____.

A. 2 cm

B. 4 cm

C. 6 cm

D. 8 cm

Doubtly Asked 27 Oct 2026 Board exam · March 2026 hsc 12th Save WhatsApp Report

1 answer

Best answer

Answer: B. 4 cm

Answer: (b) 4 cm

Intensity of magnetisation \(M_z = \dfrac{m}{V} = \dfrac{m}{A\,l}\), so

\[l = \frac{m}{M_z A} = \frac{10}{10^6 \times 2.5\times10^{-4}} = \frac{10}{250} = 0.04\ \text{m} = 4\ \text{cm}\]

Doubtly AI · 27 Oct 2026 AI-verified · Oct 2026 Report

Was this answer helpful?

A bar magnet of magnetic moment 10 A m\(^2\) has a cross-sectional area of \(2.5 \times 10^{-4}\) m\(^2\). If the intensity of magnetisation of magnet is \(10^6\) A/m, the length of the bar magnet is _____.

1 answer

Your answer